It is very difficult to find thin films which are opaque (or translucent) to visible and ultraviolet light, insulating, non-ionic, tolerant to high temperature processing, nonmetallic and compatible with integrated circuit processing. Using a metal layer as an opaque layer is not optimum because the processing becomes more costly and complicated. The use of metal requires an additional mask step in order to avoid shorting a semiconductor's pads together during assembly and cannot be used in processes that require temperatures above 450.degree. C. Using metal also adds capacitive coupling to the integrated circuit that is significant and undesirable. In addition, the use of metal will effectively shield radio frequency transmissions from the I.C. This is deleterious for an Radio Frequency Integrated Circuit (RFIC) with on-chip antennas.
Standard integrated circuits require an ultraviolet light blocking material to function properly, which standard encapsulation normally provides. For novel packages that allow light into portions of the package it is necessary to block out light to an integrated circuit over the entire chip with the exception of a photocell area or photo detector area. Electron-hole pairs are generated by incoming light and this interferes with the normal function of transistors and other light sensitive circuit elements designed to operate in darkness. An ideal material for accomplishing this task would be a non-conducting opaque material that would avoid requiring another mask which increases production costs and processing complexity.